Miniature Cooling in Laser Hair Removal Systems

Laser hair removal is one of the oldest laser aesthetic techniques with the first devices appearing on the market in the mid-nineties.  The process uses a pulsed laser to selectively target the basal stem cells inside the hair follicles without damaging the surrounding tissue and the skin.  Wavemed, SRL (San Cesareo, Italy) is an established aesthetic system manufacturer and innovator in developing laser hair removal devices.

We talked with Mirko Gavini, Biomedical Engineer of Wavemed, to discuss their Modula LD system.

“Historically, laser hair removal systems were bulky and heavy.  Our design goal was to create a tabletop device using different wavelengths which allows us to provide guaranteed epilation by selecting the best wavelength based on hair color and skin pigmentation” Gavini said.

Gavini further noted that “diode laser modules were the obvious choice for our application.  These readily available laser sources are offered in a wide range of wavelength options and are dramatically smaller when compared to other lasers. Diode lasers offer high (>50%) efficiency and long lifetimes, in excess of 50,000-hours.

“We knew our biggest challenge was cooling the diodes.  When using laser diodes with 1kW of optical output, we need to remove 500 Watts or so of heat to maintain a diode temperature of 25 degrees C. Conventional stand-alone laser chillers are three times larger than our enclosure and were quickly ruled out” observed Gavini.  “We evaluated Thermal Electric Cooling (TEC) but discovered early on that there were severe limitations.  The size was still too large to fit into our enclosure and the efficiency is poor.  TEC’s generate over 1 kW of heat, which is dumped into the room.  The low efficiency required large fans to reduce the heat but were too noisy for a clinical environment.”

“Aspen Systems’ Liquid Chiller Module (LCM) proved to be ideally-suited to meet our requirements for small size, low weight, high efficiency, and quiet operation,” Gavini stated.  “Aspen’s LCM has been instrumental in our success.  We now promote our Hpc (High power cooling) technology made possible with the Aspen chiller.”

Maximum power in the smallest space
The secret of its compactness is in the Hpc High power cooling technology. It uses a latest generation chiller system, which overcomes the most cumbersome past technology, and is able to quickly dissipate the heat produced by the high power of the diode. Thanks to careful design geared around performance, power becomes functional in reducing dimensions.